ISHair: Importance Sampling for Hair Scattering

We present an importance sampling method for the bidirectional scattering distribution function (bsdf) of hair. Our method is based on the multi‐lobe hair scattering model presented by Sadeghi et al. [ [SPJT10] ]. We reduce noise by drawing samples from a distribution that approximates the bsdf well. Our algorithm is efficient and easy to implement, since the sampling process requires only the evaluation of a few analytic functions, with no significant memory overhead or need for precomputation. We tested our method in a research raytracer and a production renderer based on micropolygon rasterization. We show significant improvements for rendering direct illumination using multiple importance sampling and for rendering indirect illumination using path tracing.     

基于FSM模型检验的安全测试技术研究

安全性、可靠性是计算机软硬件系统达到用户满意度的重要指标,为了保证其安全,在系统投入使用之前必须要经过严格的安全性测试。提出一种基于FSM(Finate State Machine)和FTA(fault tree analysis)的模型检测的形式化安全性测试方法来验证被测系统的安全性。该方法具有较高的通用性,能详细地分析软件模型可能出现的故障。     

基于光斑室内移动机器人的定位导航技术

现代建筑室内结构日益复杂化,特别是伴随人口老龄化的加剧,家庭安全问题引起人们广泛关注。为了解决室内定位与导航的问题,提出基于光斑室内移动机器人的定位与导航技术,依靠机器人自带红外发射装置与外带摄像头相结合,实现室内情况下对机器人的精确定位与准确导航,并且可以广泛应用于扫地机器人、家庭监控机器人等家庭服务机器人,为实现机器人自动路径规划、自动充电、自动巡航、自动避障等功能提供保障。     

洗衣机旋转系统驱动特性的研究

对电动洗衣机负载的稳态转矩转速特性进行实验研究,理论分析了洗衣机旋转系统的动力学特性,因此提出了对变频洗衣机的控制方式和电动机设计的有关考虑,并进行了实验。     

逐点插入法在三维地质可视化系统中的应用研究

逐点插入算法是一种依次插入数据点来解决曲面三角网格化的方法.此种方法可以实现平面域上离散数据点的De-launay三角网格化。本文深入研究了此种算法,并将此算法运用到三维地质模型可视化软件系统的设计中,取得很好的效果。     

无取向硅钢热轧板形控制与轧制特性的关系

无取向硅钢板形质量要求日趋严苛。热轧是控制无取向硅钢成品横截面厚差偏大、尤其是边部减薄显著的关键工序。通过测试并分析无取向硅钢板形控制与专有轧制特性的关系,提出可通过采用合理的ASR非对称自补偿工作辊和常规工作辊的辊形配置及相应的窜辊策略可有效控制带钢边部减薄和凸度,使板形质量达到用户要求。     

Using group communication to monitor web-based group learning

Abstract  In a web group-learning environment, students must communicate with other group members on the Internet to accomplish group projects and share knowledge. Communication is likely to affect performance and so analysing the relationship between communicative relationships and group performance may help teachers to monitor groups effectively. Certain tasks are necessary to perform such an analysis — recording group communication, extracting communication relationships and determining the relationship between group communication and group performance. This study developed a method for determining relationships and rules for predicting performance to enable teachers to take act appropriately according to the predicted performance of the group. Four group performance indicators are considered — average grades within a group, project grade, frequency of resource-sharing and drop-out rate. Experimental results are presented, concerning the application of the methodology to a web class of 706 students, divided into 70 groups. The experimental results show that group communication patterns significantly affect group performance.     

Design and Implementation of Fuzzy Sliding-Mode Controller for a Wedge Balancing System

In this paper, we address the design and implementation of fuzzy sliding-mode controller for balancing a wedge system. At first, we examine the mathematical model of the wedge balancing system. The dynamic system is complex and ill defined; hence we propose the fuzzy sliding-mode control (FSMC) method to achieve the control objective. The proposed control method enhances the ability of fuzzy logic control so that the minimal number of fuzzy inference rules is systematically obtained even the plant parameters are unknown. Both computer simulations and real-time experiments are exploited to demonstrate the validity and feasibility of the developed control scheme.     

油酸改性纳米ZrO2粉体及其机制研究

采用水热法制备了平均粒径小于10nm左右的氧化锫.用油酸对纳米ZrO2粉体进行了表面改性,研究了改性工艺条件中油酸添加量对亲油改性效果的影响.按质量百分比油酸:乙醇:水=l:2:2的比例配制改性剂,油酸添加量为ZrO2的lO%(摩尔分数)时,改性的ZrO2粉体在二甲苯中分散稳定性最佳.通过FT-IR分析表明,油酸与纳米ZrO2是以氢键和共价键两种形式结合,在无机纳米粒子表面形成单分子膜.     

反对称角铺设层合矩形板在不同边界条件下的后屈曲问题

本文以板的无量纲最大挠度为摄动参数,应用摄动法研究了在几种支承情况下,反对称角铺设层合矩形板的后屈曲问题,并以梁的特征函数所构成的广义付里叶级数作为高阶摄动偏微分方程的近似解,本文方法简捷,计算收敛性好、数据可靠。